Kuparuk River. Photo by Jon Benstead.
Since 1983, the Streams Project at the Toolik Field Station has monitored physical, chemical, and biological parameters in a 5-km, fourth-order reach of the Kuparuk River near its intersection with the Dalton Highway and the Trans-Alaska Pipeline. In 1989, similar studies were begun on a 3.5-km, third-order reach of a second stream, Oksrukuyik Creek.
In each river, physical conditions (such as discharge and temperature), nutrient levels, primary production, insects, and fishes are monitored throughout the summer. Also, we conduct experimental fertilization of the Kuparuk River and Oksrukuyik Creek to determine the effects of added phosphorus and nitrogen on primary productivity, insect communities, and fish growth in arctic rivers.
We are using this information to predict the relative importance of "bottom-up" and "top-down" controls in arctic stream ecosystems. [Note: 1996 was the last summer that Oksrukuyik Creek was fertilized.]